You are correct in each of your statements. You DID suck last round (-9.71%), but our good buddy ECHOS sucked the royal big one even worse (-14.48%)! Of course, it was a brutal period for VMC's.
You are also correct that randomness plays a part. You never know how your opponent will do in any given week. However, ON AVERAGE, the better you do, the better your odds of winning any given round - and over the course of the contest. I think the previous 4 PSL's where we had the contest are pretty representative of what to expect. Shown are the winners of the tournament and their ranking at the end of the contest.